SQL 2008 and 2008 r2 support and difference

1) are sql server 2008 and sql server 2008 r 2 2 completely different products? If so what are the main differences between the 2.

2) Is SQL 2008 R2 SP1 still supported? If not what is the latest SP level, and how long has SP1 been out of support for? I appreciate there is the MS lifecycle site, but I am not to confident on this so could do with a steer on remaining support?

3) if you have a HA setup for SQL, do all your servers need to be running the same SP level for the SQL software? or can you get away with running different versions on different servers.

The purpose of this paper is to provide you background on SQL Server. It’s your self-study guide for learning fundamentals. It includes both the history of SQL and its technical basics. Concepts and definitions will form the solid foundation of your future DBA expertise.

CCModeler offers a way to enter basic information like entities, attributes and relationships and export them as yEd or erviz diagram. It also can import existing Access or SQL Server tables with relationships.